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Telephony
The translation of sounds into electrical signals that are carried over wires or radio waves and then converted back to sound.

Third generation wireless (3G)
A group of wireless technologies that move from circuit-switched communications to wireless broadband, high-speed, packet-based networks. These are preceded by first generation analog, and second-generation digital, communication technologies.

Three-tier
A type of client/server architecture made up of three separate processes. The back-end tier stores the data in a database server, the middle tier runs an application server that handles most of the processing, and the user-facing tier runs on users' computers.

Time Division Multiple Access (TDMA)
A wireless protocol that allows large numbers of users to access one radio frequency by allocating time slots for use to multiple voice or data calls.

Time sharing
The concurrent use of a computer by more than one user. Mainframes are time-sharing systems, most PCs are not.

Transmission control protocol/Internet protocol (TCP/IP)
The most common Internet communication protocol. The higher layer, TCP (transmission control protocol), assembles files into smaller packets that are transmitted over the Internet and received by another TCP layer that reassembles them. The lower network layer, (IP) Internet protocol, handles the address part of each packet so that it gets to the right destination.

Tunneling
The practice of connecting two computers securely and privately over a series of public links.